package day.day7_15;
import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        while(scan.hasNext()){
            int m=scan.nextInt();
            System.out.println(num(m));
        }
    }

    public static int num(int m){
        if(m==1) return 1;
        if(m==2) return 1;
        return num(m-1)+num(m-2);

    }
}